The large digital display on the UPLY Digital Aquarium Thermometer is easy to read due to the large numbers. The best aquarium thermometer is the one that you can rely on. Do not place the thermometer in direct sunlight, or near a heating or cooling unit. This removes the need for wires, making your fish tank look less messy. Then I can't read them without sticking my hand in the tank. they seem pretty accurate to me, although I don't have any proof of that. I get how it works but it shows different colors and It shows them 2 at a time. I think it's only 3 colors but it can be more. BelleK. Relevance. A: Stick-on thermometers are easy to use and can be placed on the side of the aquarium. That said, it should be noted that they are to be kept away from direct sunlight or cooling/heating units, as this affects the reading and accuracy. the strip thermometer i'm using (by ATI) says no the instruction that the lowest temperature (colored BLUE) is 2 degrees lower than the actual temperature, the higher temperature (colored BROWN) is 1 degree higher, and the middle temperature (colored GREEN) is the actual tank temperature. I use the stick on tank thermometers myself. Answer Save. The thermometer is submerged in the water because it has a built-in sensor. 4 Answers. It's a marina themometer sticker. i've found mine easy to use and pretty accurate. Operating the device is simple too. My cichlids like to move the "inside" tank thermometers. A stick-on thermometer goes on the outside of an aquarium. It can go on the front, back, or side of the tank. These areas can affect thermometers reading. i'm treating for ich right now and put the … What We Like About UPLY Digital Aquarium Thermometer. General placement of the thermometer may vary depending on what type of thermometer that you have. How do u read a sticker thermometer on an aquarium? In general, aquarium thermometers are rather inexpensive pieces of equipment but help monitor one of the more critical aspects of your aquarium. I've seen blue green and brown.